TEMPERATURE CONTROLLED/LIMITING HEATING ELEMENT FOR AN ELECTRIC COOKING APPLIANCE

• US 20120125912A1
• Filed: 11/24/2010
• Published: 05/24/2012
• Est. Priority Date: 11/24/2010
• Status: Active Grant

• Current Assignee: Pioneering Technology Corp
• Original Assignee: Pioneering Technology Corp
• Inventors: CALLAHAN, Kevin, SHAH, Reza, Callahan, Peter M., Hu, Yibing
• Granted Patent: US 8,723,085 B2
• Time in Patent Office: Days
• US Class Current: 219/494
• CPC Class Codes: F24C 7/087 of electric circuits regulating heat
• CPC Class Codes: H05B 1/0266 Cooktops
• CPC Class Codes: H05B 3/70 Plates of cast metal

Abstract

A temperature controlled/limiting heating element for an electrically powered cooking appliance, having: a plate with an upper contact heating surface; a pair of heating element terminals adapted for removably engaging electrical power supply terminals of the electrically powered cooking appliance; a plurality of resistive heating wires, in thermal engagement with a lower surface of the top plate, comprising: a non-cycling resistive heating wire connected in series to the heating element terminals; and a cycling resistive heating wire connected in series to the heating element terminals via a thermostat switch in thermal engagement with a lower surface of the top plate, wherein the thermostat switch is normally closed when exposed to a sensed temperature below a set temperature and the thermostat switch opens when the sensed temperature is equal to or exceeds the set temperature.

Claims

1. A temperature controlled/limiting heating element for an electrically powered cooking appliance, comprising:

a plate with an upper contact heating surface;

a pair of heating element terminals adapted for removably engaging electrical power supply terminals of the electrically powered cooking appliance;

a plurality of resistive heating wires, in thermal engagement with a lower surface of the top plate, comprising;

a non-cycling resistive heating wire connected in series to the heating element terminals; and

a cycling resistive heating wire connected in series to the heating element terminals via a thermostat switch in thermal engagement with a lower surface of the top plate, wherein

the thermostat switch is normally closed when exposed to a sensed temperature below a set temperature and the thermostat switch opens when the sensed temperature is equal to or exceeds the set temperature.

2. The temperature controlled heating element of claim 1 wherein the set temperature is in the range of 370°

C. to 450°

C.

3. The temperature controlled heating element of claim 2 wherein the set temperature is in the range of 400°

C. to 420°

C.

4. The temperature controlled heating element of claim 1 wherein the thermostat switch has a nominal current load capacity of 10 Amps at 250 Volts AC.

5. The temperature controlled heating element of claim 4 wherein the thermostat switch has a duty life of no less than 10,000 cycles.

6. The temperature controlled heating element of claim 1 comprising at least two cycling resistive heating wires.

7. The temperature controlled heating element of claim 1, wherein the plate includes an outer peripheral wall.

8. The temperature controlled heating element of claim 7, wherein the plate includes an inner wall defining a chamber in which the thermostat switch is housed.

9. The temperature controlled heating element of claim 8 wherein, the non-cycling resistive heating wires and the cycling resistive heating wires are disposed between the inner and outer walls.

10. The temperature controlled heating element of claim 9 wherein, the non-cycling resistive heating wires and the cycling resistive heating wires are embedded within a refractory layer.

11. The temperature controlled heating element of claim 10 wherein the refractory layer is formed from a wet castable refractory composition.

12. The temperature controlled heating element of claim 4 wherein the cycling resistive heating wires are configured in a series circuit having a current resistance in the range of 4 to 8 Amps at 250 Volts AC.

13. The temperature controlled heating element of claim 12 wherein the cycling resistive heating wires are configured in the series circuit having a current resistance in the range of 5 to 7 Amps at 250 Volts AC.

14. The temperature controlled heating element of claim 8 wherein the plate has a plate thickness and includes a platform on which the thermostat switch is mounted with a platform thickness greater than the plate thickness.

15. The temperature controlled heating element of claim 7 comprising a cover disposed:

inward of the outer wall; and

beneath the wires and thermostat switch, the cover being mounted to the plate with a fastener.

16. The temperature controlled heating element of claim 15 wherein the plate includes a central boss with a threaded bore and the fastener comprises a threaded shaft passing through the cover.

17. The temperature controlled heating element of claim 15 wherein the pair of heating element terminals include:

a pair of terminal wires in electrical communication with the thermostat switch, the non-cycling resistive heating wire and the cycling resistive heating wire, the pair of terminal wires passing through the cover;

an inner insulative ceramic block disposed between the plate and the cover, the inner ceramic bloc surrounding the pair of terminal wires; and

an outer insulative ceramic block disposed beneath the cover and engaging the inner ceramic bloc, the outer insulative ceramic block having a pair of connectors engaging end portions of the pair of terminal wires extending downward from the inner block.

18. The temperature controlled heating element of claim 1 wherein the plate is formed of sintered cast metal powder.

19. The temperature controlled heating element of claim 7 wherein the outer wall includes mounting tabs.

20. The temperature controlled heating element of claim 4 wherein the outer wall includes hot air vent notches between the mounting tabs.